Abstract

There was a small decrease in grain yield (from 10.8 to 10.5 t ha−1) when wheat straw (3 t dry matter ha−1) was incorporated into a silty clay loam soil sown to winter wheat. In the absence of straw, 60% of autumn-applied 15N-labelled nitrate was lost from the crop:soil system. Straw incorporation decreased this loss to 47%. There was little overall effect on the uptake of N by the crop, presumably because straw immobilised inorganic N that would otherwise have been leached from the soil during winter. Only 12% of the N in 15N-labelled straw was recovered by the crop; 78% still remained in the soil one year after incorporation.